It entered the 2006 season as the home of the defending champs (Pittsburgh) and with a chance to become a real power division, thanks to a rising force in Cincinnati and a rejuvenated Baltimore team that finally had a legitimate NFL quarterback. There was even hope in Cleveland, under second-year coach/defensive wunderelder Romeo Crennel.

But it all unraveled as quickly as it took Ben Roethlisberger's face to fly into a Pittsburgh windshield (on a car, the conspiracy theorists among us seem to have forgotten, that was driven by a New Englander).

The Steelers tumbled through a frustrating 8-8 season. The Bungles do what the Bungles always do, and disappointed their fans. The Browns continued to be one of the most inept teams in football. The Ravens surprised everyone with a 13-3 record, a division title, and the best all-around team in football entering the postseason. Then they collapsed at home on national TV, and failed to score a single TD in the division's lone playoff game.

Will it be any better in 2007? The Fillability Index gives us our earliest indicators.

The lasting image of the 2006 Ravens is probably of QB Steve McNair, having one of the worst games of his career (49.9 passer rating) in Baltimore's 15-6 loss to Indy. But McNair and the passing game weren't the fatal flaw for this otherwise excellent football team: that fatal flaw was Jamal Lewis and the running game.

Despite a good offensive line (7th in our Offensive Hog Index), Lewis and the Ravens averaged just 3.44 YPA in 2006. Only the historically inept running game of Arizona was worse (3.19 YPA). Lewis bears the brunt of the blame. He got the bulk of the workload (314 carries) yet averaged just 3.61 YPA. His numbers in the playoff loss (13 carries, 53 yards, 4.08 YPA) don't begin to tell the story. The beefy Ravens were blowing the smallish Colts off the line that day, but Lewis could do nothing with the gaping holes provided him.

So the Ravens made what could be the most brilliant move of the offseason, adding Willis McGahee in trade. Just as the trade for McNair last season filled a glaring need, so does this acquisition. On paper, it's not much of an upgrade – McGahee averaged 3.8 YPA last year to 3.6 YPA for Lewis – but McGahee last year was running behind the league's 31st-ranked O line in Buffalo (according to our Hog Index), and is five years younger than Lewis. Even if McGahee is just O.K., the Ravens will have made a big leap in the running game.

The Baltimore defense was clearly the best in football last year, leading the league in five of seven categories we look at to rank teams. The loss of multi-dimensional linebacker Adalius Thomas may hurt, but for the money he wanted Baltimore probably made a wise, value-oriented decision not to keep him. The loss of one player won't ruin that defense, though they have done little to replace him, either.

Other than that, there were no real holes to fill. With the offense ranked 17h in yards and 12th in scoring, the Ravens wisely drafted for that side of the ball with their top three picks, adding two linemen and a wideout. Basically, the Ravens did everything in their power to ensure that the running game won't be their downfall again in 2007.

The Browns have a long way to go, and like fellow cellar-scrapers Detroit and Oakland, they recognize it. While they still have some holes to full on the defensive line, no team did more to fill their most glaring need.

In Cleveland's case, it was the offensive line. If you were wondering why they picked tackle Joe Thomas with the No. 3 pick overall in the draft instead of a high-profile skill-position player, consider that the Browns were 29th in yards per rush (3.59) and 31st in negative pass plays allowed (13.98 percent of dropbacks) and 30th overall in our Offensive Hog Index. So they added the two best linemen available in the offseason, veteran guard Eric Steinbach from the Bengals and top college prospect Thomas. You can't ask for much more, although it was long overdue – the Browns had only used two first-day picks on offensive linemen since being reborn in 1999.

Add to those two the healthy return of center LeCharles Bentley, and the Browns all of a sudden could have one of the best OLs in the league – if first-year OL coach Steve Marshall, last seen getting David Carr killed as Houston's unit coach, can pull it together.

With TE Kellen Winslow and WR Braylon Edwards looking like stars, there's a nice nucleus there to improve an offense that ranked 29th in passing yards per attempt last year. Unfortunately, the nucleus is filled out by a washed-up tailback (Jamal Lewis) and a collection of inexperienced QBs. Brady Quinn could find success behind the revamped line, but Lewis almost certainly won't (3.4 YPA in 2005, 3.6 YPA in 2006).

The defense wasn't exactly great in 2006 (22nd in scoring), but it was better than the offense. The Browns did some man-for-man switching on the DL and in the secondary, which probably won't amount to much. Their chances of success will come with the maturation of young talent, sometimes a dicey proposition.

The Browns are playing in a potentially tough division, and a bad finish in 2007 will be costly because they traded their 2008 first-rounder to acquire Brady Quinn. But if Lewis has some life in those legs, and Quinn plays more like Matt Leinart than Ryan Leaf, that sacrificed No. 1 might not be as high as people think.

Did the inept Bengals of old find their way back to Cincinnati sometime after the new year?

Solid contributors have been streaming out of Cincinnati, and not because they're fleeing the law. The Bengals have taken some major personnel hits, losing four full-time starters and one key special teamer (Tony Stewart) without replacing them.

They addressed their need in the secondary with a first-round DB (Leon Hall), but ignored their defensive front seven. They were 19th in both negative pass plays forced and yards-per-carry allowed in 2006, and overall ranked 23rd in our Defensive Hog Index, and are apparently banking on full seasons from LBs Odell Thurman (head case) and David Pollack (broken neck).

Their offensive line, which took a major step back last year, lost G Eric Steinbach and added journeyman Alex Stepanovich. Again, the Bengals seem to be hoping that their struggles last year were thanks to injury (T Levi Jones missed 11 starts) and that things will be better when all is well.

The running game wasn't great in 2006 (25th in yards per attempt), but with only two first-day picks, why choose RB Kenny Irons? Rudi Johnson was O.K. in 2006 and great in 2005, and backups Kenny Watson and Chris Perry seem to be able. An odd choice for a team with so many other needs.

The Bengals still have a great passing attack, and the defense was respectable in scoring defense (17th, 20.7 PPG) a year ago. But they figure to be awfully thin. Their depth was a problem last year, and now it's going to be significantly thinner with the loss of so many veteran players.

Their biggest problems in 2006 came on both lines, and they took steps back on both fronts.

Pittsburgh's 2006 season felt a lot worse than it looks in retrospect, and they have fewer holes to fill than just about anyone this offseason ... with the notable and underappreciated exception of the head coach. If Pittsburgh struggles this fall, no coach will be under more pressure than Mike Tomlin.

Few have been as consistently good as Bill Cowher and the Steelers over the past 15 years. And it's always been a good question: did the Steelers have so much talent and success because they drafted well, or because Bill Cowher "coached them up"?

We'll find out. Tomlin may well be an excellent coach, but he's a total unknown replacing one of the most proven "knowns" in the game.

Doesn't seem like a hole well filled, at least not in the first season.

On the field, the Steelers of 2007 should look like the Steelers of 2006 – and that's a good thing. Despite the Super Bowl hangover (what were those guys drinking?) and the Ben Roethlisberger chronicles, Pittsburgh has a solid team and will again.

They were extremely well balanced, ranking in the top half of the league in almost every category except winning. They were unfocused without the leadership of Jerome Bettis, and they were snake bitten in a top-heavy AFC. But it was a carbon copy of the Super Bowl team of 2005, both on the roster and on much of the stat sheet.

The Steelers made a straight swap at outside linebacker, cutting Joey Porter and drafting rookies Lawrence Timmons and LaMarr Woodley. (History says the Steelers likely made the right move; they've had great linebackers since Hendrix played "Star Spangled Banner" at Woodstock.)

But other than that, this is the same basic team that won the Super Bowl. It's a quality bunch, for sure, and not usually the stuff of a rookie coach's regime.